Swiss-type claim, i.e. pharmaceutical use claim, is a special category of claims in patent applications in the field of medicine and refers to a claim which covers the second or subsequent medical use (or indication) of a known substance or compound. Swiss-type claims were first creatively proposed by the Swiss Intellectual Property Office and are designed to protect the medical use of substances.

In drafting Swiss-type claims, the medical use of a substance is written as the use of a substance in the preparation of drugs for the treatment/prevention of a disease, cleverly turning the medical use into a manufacturing use, so that the doctors’ freedom to practise medicine will not be influenced and meantime such claim will meet the requirements for being a subject matter of patent protection.

The inevitable emergence of Swiss-type claims has its reasons. In the research and development of drugs, there are often cases where the drug lacks enough effectiveness or produces unexpected effects. Accordingly, the R&D will turn to focus on the new uses of the known substance, which also help reduce the risk comparing to developing new drugs. Such a research involves relatively high scientific level, which needs a huge amount of human, material and financial resources to be invested in. It will be unfair to not allow the result of such a research to be eligible for patent protection as it is new, unpredictable and not obvious compared with existing technology. With the evolvement of practice, some jurisdictions now accept medical use claims, so Swiss-type claims gradually withdrew from the historical stage and was no longer used or recognized there, while in China, Swiss-type claims are still widely used.

Some Swiss-type claims require a mechanism to characterize pharmaceutical use. A pharmaceutical use claims characterized by a mechanism does not directly characterize the indication by the name of disease, but limits the range of the diseases involved by the mechanism of the cause of the diseases or the mechanism of the treatment of the diseases.

Examples of Swiss-type claims are listed below for understanding the characterization:

-Use of compound A in the preparation of drugs for the treatment of diseases related to B receptor anti-binding agents;

-Use of compound A in the preparation of drugs with protease b receptor antagonistic activity;

The above-underlined parts are mechanism characterizations.

For such claims, because the pharmaceutical compositions containing compound A may have been known to the public, whether the diseases characterized by mechanisms possess novelty and inventive step becomes the focus of the examination.

A common phenomenon with regard to the claims defined by mechanisms is that the use of compounds in the treatment of the disease or "similar" diseases has been made public by prior arts, but the treatment mechanism has not been disclosed. In such cases, examiners tend to raise inventive step objections.

We encountered the aforementioned problem and finally overcame the inventive step objection. We hope you would get some inspiration on the drafting of pharmaceutical use claims characterized by mechanisms and on how to respond to examiners’ objections to such claims.

The examination focus in this case is mainly the inventive step of claim 1. Claim 1 is a Swiss-type claim that defines "Use of a live attenuated Bordetella pertussis strain in the preparation of a pharmaceutical composition for eliciting an immune response capable of reducing the severity of an allergic skin inflammation in a mammal in need thereof".

In the first Office Action, the examiner cited a reference document, which mainly relates to asthma, an allergic disease, and concluded that: the difference between this application and the disclosure in the reference document is only that the diseases treated are different, and both diseases belong to allergic diseases, and their pathogenesis have common points, and thus a person skilled in the art has the motivation to use live attenuated Bordetella pertussis strain to antagonize or treat allergic skin inflammation and has the expectation of success in it, so claim 1 does not possess inventive step. In the observations, we stated that the reference document discloses the treatment of a T-lymphocyte helper type 2-dominated allergic disease, while the allergic skin inflammation treated in this claim 1 is T-lymphocyte helper type 1 (Th1)-dominated (which was not defined in claim 1, but there was corresponding content in the specification). After several rounds of discussion, the examiner eventually accepted the scheme of defining the allergic skin inflammation as “T-lymphocyte helper type 1 (Th1)-dominated”.

This case was finally accepted because it satisfied the following two conditions:

1. The specification has clear recitation of the mechanism of the disease and includes experimental data as support, which provides a solid basis for subsequent arguments and claim amendments;

2. The newly added mechanism characterization is different from that documented in prior arts, so it should be considered as a completely new application area relative to the prior arts.

Meanwhile, it should be stressed that when preparing an application document containing Swiss-type claims, the applicant should include, in addition to literal recitation, experimental data to prove its effect. If it is a new treatment mechanism, the applicant should record and prove, through comparative experiments, which diseases can be affected by the new mechanism and provide the experimental data about the effects brought by the new mechanism. The generalization in the claims also needs to be reasonable, and when drafting Swiss-type claims, the applicant may adopt intermediate generalization or specific limitation, depending on the amount of the spectrum of diseases affected.